A control device of this kind is a so-called "load sensing" controller in which the fraction of the delivery flow which reaches each actuator is determined by means of a flow controller that is pressurized as a function of the opening area of the associated control valve. Thus the displacement setting of the pump is set as a function of the actuator loads, which are transmitted to the adjusting device of the pump by means of load-pressure feed-back lines.
The flow controller usually comprises so-called pressure compensators, which perform the flow control by ensuring a constant pressure difference of 10 to 20 bar. With this "load sensing" principle the delivery adjustment occurs with a pressure difference of approx. 10 to 20 bar from the load pressure values, which can result in oscillation problems. The above-mentioned upper limit of the pressure difference is relative to normal load pressure values of 400 bar.